Power production control method based on power production rate requirement

ABSTRACT

A control system for an energy production facility includes a plant controller for receiving an indication of a measured power output of the energy production facility that includes power generators and produces output signals. The system also includes a processing unit operably coupled to the plant controller and responsive to executable computer instructions when executed on the processing unit cause the plant controller to: create an output signal that causes an energy storage device to discharge in the event power reserves of the power generators can not met the requested ramp down rate; and create an output signal that causes the energy storage device to charge up in the event that the power capability of the power generators can meet the requested ramp down rate.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY CLAIM

This application is a divisional Ser. No. 12/582,053, of U.S. Pat. No.7,908,036, entitled “POWER PRODUCTION CONTROL SYSTEM AND METHOD”, filedOct. 20, 2009, which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to energy production and, inparticular, to controlling energy production facilities in the presenceof variable production capabilities.

The production of energy in the form of electricity may take many forms.At the center of nearly all power stations is a generator, a rotatingmachine that converts mechanical energy into electrical energy bycreating relative motion between a magnetic field and a conductor. Theenergy source harnessed to turn the generator varies widely. One energysource is wind.

A wind farm is a group of wind turbines in the same location used forproduction of electric power. Individual turbines are interconnectedwith a medium voltage (usually 34.5 kV) power collection system and acommunications network. At a substation, this medium-voltage electricalcurrent is increased in voltage with a transformer for connection to thehigh voltage transmission system. The high voltage transmission systemis often referred to as a “grid.”

A large wind farm may consist of a few dozen to about 100 individualwind turbines, and cover an extended area of hundreds of square miles(square kilometers). A wind farm may be located off-shore to takeadvantage of strong winds blowing over the surface of an ocean or lake.

As is well known, electricity generated from wind can be highly variableat several different timescales: from hour to hour, daily, andseasonally. Annual variation also exists, but is not as significant.Because instantaneous electrical generation and consumption must remainin balance to maintain grid stability, this variability can presentsubstantial challenges to incorporating large amounts of wind power intoa grid system. Intermittency and the non-dispatchable nature of windenergy production can raise costs for regulation, incremental operatingreserve, and (at high penetration levels) could require an increase inthe already existing energy demand management and load shedding. Howeverthese challenges are no different in principle to the substantialchallenges imposed by other forms of generation such as nuclear or coalpower, which can also show very large fluctuations during unplannedoutages and have to be accommodated accordingly.

Currently, wind farms are operated based on the “ramp rates” of theparticular wind turbines. The ramp rate for a particular turbine (orcollection thereof) is expressed in kilowatts/second and represents therate of change in power production that the wind turbine can provide atnormal operating conditions. Each individual turbine may have a ramp uprate and a ramp down rate representing, respectively, the change band ofupper and lower limits of the power production of the turbine. The windfarm as a whole may have a total output referred to herein as the farmramp rate (RR_(farm)), which is the aggregate of all of the power changeprovided to the power collection system.

Utility companies in general, and those connected to a wind farm inparticular, have the requirement to keep the power grid they create outof fluctuations caused by high produced power changes. That is, theremay be spikes in RR_(farm) caused by increases in wind rate that need tobe avoided.

In the even that wind speed increases, the additional power created maybe shed so that the wind farm as a whole produces a constant output. Theshedding may be accomplished by ramping the power output down from onelevel to another. That is, the conversion rate of one or more of thewind turbines is ramped down (based on a ramp down signal) from onelevel to a lower level to create a lower power output. This, however,leads to the loss of power that could otherwise have been created by thewind turbine if running at a higher conversion rate.

In the event that wind decreases, the efficiency is ramped up to meetthe output demands (based on a ramp up signal). That is, the conversionrate of one or more of the wind turbines is ramped up from one level toa higher level to create a power output that meets the demand. However,in the event of a large decrease in wind, regardless of conversionefficiency, at present there may be no way to meet the power productiondemands. Thus, the utility must find other ways to provide the neededpower. This may include, for example, including a diesel generator atthe wind farm that is brought on-line when wind speed decreases in anattempt to keep RR_(farm) at or above the desired rate.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, a control system for an energyproduction facility is provided. The control system includes a plantcontroller for receiving an indication of a measured power output of theenergy production facility that includes power generators and producesoutput signals. The system also includes a processing unit operablycoupled to the plant controller and responsive to executable computerinstructions when executed on the processing unit cause the plantcontroller to: create an output signal that causes an energy storagedevice to discharge in the event power reserves of the power generatorscan not met the requested ramp down rate; and create an output signalthat causes the energy storage device to charge up in the event that thepower capability of the power generators can meet the requested rampdown rate.

According to another aspect of the present invention, a wind farm isprovided. The wind farm of this aspect includes a power collectionsystem and at least one wind turbine generator coupled to the powercollection system. The wind farm of this aspect also includes at leastone energy storage device coupled to the power collection system and asensor coupled to the power collection system for measuring a rate ofpower production of the wind farm. The wind farm of this aspect alsoincludes a plant controller coupled to the at least one wind turbinegenerator, the at least one energy storage device and the sensor. Theplant controller causes the at least one energy storage device to storeenergy in the event that the rate of power production of the wind farmexceeds an output requirement and causes the at least one energy storagedevice to discharge energy in the event that the rate of powerproduction of the wind farm is less than the output requirement of thewind farm.

In yet another aspect of the present invention, a method of operating apower production facility is provided. The method of this aspectincludes receiving at a plant controller a current power production rateof the power production facility; determining at the plant controllerthat the current power production rate is either below or above a powerproduction rate requirement; transmitting a signal from the plantcontroller to cause a power producing device to charge an energy storagedevice in the event that power production rate is above the powerproduction rate requirement or to cause the energy storage devicedischarge in the event that the power production rate is below the powerproduction rate requirement.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWING

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a block diagram showing a power production facilityimplemented as a wind farm coupled to a utility according to oneembodiment of the present invention;

FIG. 2 is a flow chart showing a method of operating a power productionfacility and charging a storage device according to one embodiment ofthe present invention;

FIG. 3 is a flow chart showing a method of operating a power productionfacility according to one embodiment of the present invention when aramp down rate is received;

FIG. 4 is a flow chart showing a method of operating a power productionfacility according to one embodiment of the present invention when aramp up rate is received; and

FIG. 5 shows a graph of the variations of ramp up rates and ramp downrates based on frequency.

The detailed description explains embodiments of the invention, togetherwith advantages and features, by way of example with reference to thedrawings.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments disclosed herein may provide an energy storage device to apower production facility. In one embodiment, the power productionfacility is a wind farm that includes wind turbine generators. Ofcourse, the power production facility could be any type of powerproduction facility and may include power production devices other thanwind turbine generators. The energy storage device may store excessenergy produced during times of high wind or when the required energy isless than what the wind farm is capable of producing given current windconditions. This stored energy may be utilized, for example, duringtimes of decreased wind to keep the level of RR_(farm) at or near adesired level. In addition, one embodiment allows the plant controllerfor the power production facility to communicate the total poweravailable from both the power production devices and the energy storagedevice to the utility so that the utility may plan accordingly. Inanother embodiment, in the event that the grid becomes unstable orotherwise operates in an out of specification manner, the ramp up andramp down rates for the power production devices may be adjusted basedon grid frequency in an attempt to match power production to powerconsumption.

FIG. 1 shows a block diagram of power production facility 100 accordingto one embodiment coupled to an electric utility 102. The powerproduction facility 100 may be referred to herein as a wind farm but itshall be understood that a wind farm is merely an example of a powerproduction facility to which the teachings herein may be applied.Accordingly, the term power production facility as used herein is notlimited to wind farms but from time to herein the power productionfacility 100 may be referred to as a wind farm for ease of explanation.

The electric utility 102 may be any producer of power that receivespower from one or more sources and provides it to other users ofelectricity. Of course, the electric utility 102 could be coupled toadditional power sources 104 other than the power production facility100 to accommodate variability in power output of the wind farm 100 dueto intermittent wind conditions. The other power sources 104 mayinclude, for example, thermal, hydroelectric or nuclear power stations,among others.

In the event that the power production facility 100 is a wind farm, itmay include one or more wind turbine generators (WTG's) 106 a . . . 106n. It shall be understood, however, that the WTGs could be other typesof power producing devices.

WTGs 106 may include turbine rotors having plurality of blades thatdrive rotors of electrical generators to produce electrical power. Theelectrical power ramp rate provided by each WTG 106 is shown asRR_(WTTx) in FIG. 1. Each of the WTGs 106 may include settings thataffect the amount of power they produce. As described above, to increasethe power output of a given WTG 106 for a particular input (e.g., windspeed), the WTG 106 receives a ramp up signal that generally limit theincrease of conversion rate of the WTG 106. Likewise, to limit thedecrease of power output of a given WTG 106 for a particular input(e.g., wind speed), the WTG 106 receives a ramp down signal thatgenerally limit the decrease of the conversion rate of the WTG 106.

The WTG's 106 may be coupled to a power collection system 107. In oneembodiment, the power collection system 107 may be implemented as amedium voltage distribution network that couples power from multiplefeeders (not shown), each feeder coupling power outputs of a pluralityof WTGs 106. In certain embodiments, power is coupled from the WTGs 106to the feeder via switching devices that may include, for example anelectrical circuit breaker. Such switching devices are generally used inwind power generation systems to shut down power generation by one ormore of the wind turbine generators during high wind conditions. In oneembodiment, the power collection system 107 couples the power ramp ratesfrom each WTG 106 (RR_(WTGa) . . . RR_(WTGx)) together to create asystem power ramp rate output expressed as RR_(farm) in FIG. 1.RR_(farm) may be a change rate expressed in kW/second.

The change rate, shown as RR_(farm) in FIG. 1, is provided to a stationsubstation 108. The substation 108 may include a transformer thatcouples RR_(farm) to a high-voltage transmission system 110. Thehigh-voltage transmission system 110 is commonly referred to as the“grid.” In particular, the transformer may increase the voltage of itsinput so it may be provided to and transported by the high-voltagetransmission system 110. The high-voltage transmission system 110 iscoupled to the utility 102.

The power production facility 100 may also include a sensor 112 coupledto the high-voltage transmission system 110. The sensor 112 measures thevoltage and current (e.g. power) output by the station substation 108.The sensor 112 may be a grid measurement device that includes voltageand current transformers. Of course, the sensor could also be coupled topower collection system 107 rather than the high-voltage transmissionsystem 110 or to both.

The sensor 112 may be coupled to a plant controller 114. In oneembodiment, the plant controller 114 is coupled via a communicationsinterface 117 to the utility 102. The facility interface 117 may allowfor bidirectional signal transfer between the plant controller 114 andthe utility 102. The facility interface 116 may be realized as acommunication network or hardware interface.

The plant controller 114 may be implemented in a variety of manners. Forexample, the plant controller could be a computing device that includesa processing unit for carrying out some or all of the processesdisclosed herein. In the prior art, the plant controller 114 providedramp rates (as either ramp up or ramp down signals) to the individualWTGs 106. In operation, a change in a ramp rate is not instantaneous.Rather, the ramp rate of the particular WTG 106 may be ramped up to meetcertain power requirements and ramped down to meet lower powerrequirements according to power production “set points” that may bereceived by the plant controller 114 from the utility 102.

In the event that the utility requests a higher power setpoint, the rampup rate of the WTG 106 is controlled to met the utility ramp uprequirements. In some instances, this may result in the WTG's 106 beingrun at less than optimal efficiency and may result in power being lost.Similarly, in the event that wind decreases, the efficiency of the WTGs106 may be increased (the WTG is ramped up according to a ramp up rate)to attempt to match the output of the WTGs to that power demanded by theutility 102. Of course, there may exist instances where the WTG's 106are not receiving enough wind to meet output requirements. The plantcontroller 114 according to one embodiment may be configured to dealwith these and other shortcomings in the prior art.

In one embodiment, the power production facility 100 may include anenergy storage device 116 coupled in parallel with the WTGs 106. Theenergy storage device 116 may be any type of device capable of storingelectrical energy for later use. Examples include, but are not limitedto, flywheels and batteries. In one embodiment, excess energy producedby the WTGs may be stored in the energy storage device 116. The energymay be provided to the energy storage device 116 through the powercollection system 107. In one embodiment, the energy storage device 116may be used to provide stored energy to the substation 108 to supplementthe energy provided by the WTGs 106.

The WTG's 106 and the energy storage device 116 are coupled to the plantcontroller 114. The plant controller 114 provides signals to the WTGs106 to vary their outputs (RR_(WTGx)) to meet certain outputrequirements. As discussed below, the WTG's 106 may not be able to meetthe power requirements and the energy storage device 116 may beramped-up to help meet the power requirement. In FIG. 1, signals tocontrol the ramp rates of the WTGs are shown as RR_(CmdWTG) and signalsto control the ramp rate of the energy storage device 116 are shown asRR_(cmdStorage). It shall be understood that the energy storage device116 may both receive power from and provide power to the powercollection system 107 depending on its configuration or operational modeat a particular time. This configuration/operational mode (charge ordischarge) is controlled, for example, by signals received by it fromthe plant controller 114.

According to one embodiment, the utility 102 may communicate with plantcontroller 114 via facility interface 117 to adjust amount of energyrequired. To meet these changes, the plant controller 114 may eitherramp up or ramp down one or more of the WTGs 106. Two values may beneeded to define a ramp rate, power span and time span. The plantcontroller 114 may monitor (either continuously or periodically) theactual power produced by the power production facility 100 with thesensor 112.

On a ramp up cycle (wind increases or the utility 102 sets an increasedpower output set point) the plant controller 114 controls the ramp ratefor the facility 100 (RR_(farm)) by sending individual command to theWTGs 106 and the energy storage device 116. During this cycle it ispossible to improve the ramp rate of the WTGs (RR_(WTGx)) and expendenergy stored in the energy storage device 116 at the same time to meetdemand. The energy storage device 116 may be charged when the possiblepower of all of the WTGs exceeds the requested power.

On a ramp down cycle (decreased power set point) the plant controller114 adjusts the power output of the WTGs 106 (via signal RR_(CmdWTG) oncommunication line 142) such that extra energy produced is first used tocharge the energy storage device 116 before ramping down of the WTGs106. This may occur until the energy storage device 116 is fullycharged. After fully charging the energy storage device 116, the WTGs106 are then ramped down to meet the lower power set point. In thismanner, at least some of the extra power that would have been lost inthe prior art is stored for later use.

In the event that wind has decreased, the plant controller 114 has nocontrol on the ramp down rates of the WTGs 106. That is, if the winddecreases to a low enough level, regardless of the operation of theplant controller 114, power production facility 100 may not be able tomeet the required set point. In this case, the plant controller 114 maybe configured to cause the energy storage device 116 (via signalRR_(CmdStorage)) to discharge to meet the adjusted ramp down rate set bythe utility. In other words, when the wind decreases and power producedby the wind farm 100 decreases faster than the ramp rate set by theutility 102, the plant controller 114 causes the energy storage device116 to discharge to meet the power requirements of the utility 102until, hopefully, the wind increases or the utility lowers the powerrequirements.

As discussed above, the plant controller 114 may be coupled via facilityinterface 117 to the utility 102. The facility interface 117 may allowfor the plant controller 114 and the utility to pass information betweenthem such as, for example, the amount of power ramp rate (e.g.,RR_(farm)) the utility 102 is requesting from the power producingfacility 100. In one embodiment, the plant controller 114 may provideelectrical variables of the configured ramp rates of the wind farm 100and the availability of these values to the utility 102. That is, theplant controller 114 may be configured to calculate the up and down ramprate availability (RR_(UpAvail) and RR_(DownAvail), respectively) thatthe power producing facility 100 may provide to the utility 102. In oneembodiment, the availability may be calculated based on the relationbetween the possible power of the power producing facility 100, thepower set point, and the charge status of the energy storage device 116.With this information, the utility 102 may be able to improve powerresource plans. For example, when the power down limit exceedsRR_(DownAvail), the utility may start one of the other power sources 104(such as a conventional power plant) to stabilize the ramp down rate.

FIG. 2 shows a flow chart of a process for controlling the operation ofa wind farm in the event that the wind is decreasing. If shall beunderstood that the process shown in FIG. 2 may be performed, forexample, by the plant controller 114 (FIG. 1). Of course, the processcould be done in other parts of the wind farm or at another location. Inthe following description, the term wind farm shall be used. However, asdiscussed above, the teachings are not limited to wind farms and may beapplied to other types of power producing facilities.

The process begins at a block 202 where it is determined that the setpoint for the wind farm desired by the utility exceeds the power outputcapabilities of the farms' WTGs running at a high or maximum conversionrate. If the WTGs could meet the set point, the process in FIG. 2 is notinvoked and the plant controller merely increases the WTG efficiency(e.g., it ramps them up) to meet the set point as in the prior art.

At a block 204, the process causes the energy storage device 116(FIG. 1) to begin discharging into the power collection system 107. Thedischarge rate of the energy storage device 116 (FIG. 1) may becontrolled such that it, in combination with the WTGs 106 (FIG. 1),meets the set point.

FIG. 3 shows a flow chart of the process for controlling the operationof a wind farm in the event that the utility lowers the power set pointof the wind farm or the power is reduced due to lower wind conditions.Ramp down rate setpoints are provides by the utility. At a block 302 alower power setpoint is received from the utility or other externalentity that may control the output requirements of the wind farm. At ablock 304 it is determined if there is enough power reserve at WTGs tomeet the requested ramp down rate. That is, at block 304, it isdetermined if the power producing capacity of the wind farm exceeds thedemand for power set by the utility. In the event that it does, the windfarm could produce more power than needed and the process moves to ablock 306. In the prior art, this excess capacity may have been lost.

At block 306 the energy storage device is charged until it is fullycharged. The rate that the energy storage device is charged will, ofcourse, depend on the amount by which the wind farm may exceed thedemand. In one embodiment, the plant controller 114 may receive anindication of the charge level of the energy storage device 116 from theenergy storage device 116 (FIG. 1). Accordingly, and referring back toFIG. 1, the energy storage communications path 140 between the plantcontroller 114 and the energy storage device 116 may be bi-direction inone embodiment.

Of course, it should be understood, that in the event that a particularwind farm has multiple energy storage devices, the process shown in FIG.3 may remain in block 306 until all of the energy storage devices arefully charged. Of course, in some instances, other external conditions(such as a change of wind conditions or a new set point is received fromthe utility) may cause the plant controller 116 to begin a new ordifferent process before the energy storage devices are fully charged.In such an instance, the process shown in FIG. 3 may terminate and thenew process begins.

At a block 308, after the energy storage device has been fully charged,the plant controller 114 (FIG. 1) may reduce the conversion rate of theWTGs downward so that the power output from them meets the ramp rate setby the utility. When the power output of the wind farm meets the new setpoint, the process shown in FIG. 3 is complete.

In the event that the WTGs can't meet the requested ramp down rate, at ablock 310 it is determined if the energy storage device is discharging.If it is, it means that the wind farm was previously relying on theenergy storage device to meet the set point and still must because ithas already been determined that the new set point exceeds the powerproducing capabilities of the WTGs. In such a case, at a block 312, thedischarge rate of the energy storage device is increased such the totalpower output of the wind farm meets the requested ramp rate received bythe utility.

If the energy storage device is not discharging, as determined at block310, it means that energy storage device has already discharged and thewind farm simply cannot meet the ramp rate received by the utility sothe process ends. Of course, there may be other processes for informingthe utility of this short fall in power production.

FIG. 4 shows another process that may be implemented in the event thatthe power production requirements of the wind farm increase. At a block402 a new power setpoint is received from the utility or other externalentity that may control the output requirements of the wind farm. Thisnew power setpoint is higher than the current power setpoint. The rampup setpoint is provided by the utility, too.

At a block 404 it is determined if the request ramp up rate exceeds thecapabilities of the WTGs. If it does not, at a block 406, the conversionrates to for the WTGs are increased to meet the new set point (new rampup rate). This is similar to what is done in a typical wind farm withoutan energy storage device.

In the event that the requested ramp up rate does exceed the currentramp up capabilities of the WTGs, processing moves to block 408 wherethe power conversion for the WTGs of the plant are improved. At a block410, the energy storage device is discharged to meet the new ramp uprate. This may include setting the discharge rate of the energy storagedevice based on the shortfall in WTG power production with respect tothe new ramp up rate.

The preceding description has been based on an assumption that that theutility provides the ramp up and ramp down rates to the plantcontroller. That is, the ramp up and ramp down rates are set points setby the utility. However, there may exist instances where the plantcontroller itself may be in a position adjust the ramp rates receivedfrom the utility to better match operating conditions.

To that end, one embodiment may include modifying the value of RR_(farm)(and ultimately, the RR for each WTG) based on the frequency of thepower grid (e.g., the frequency of the high-voltage transmission system110 of FIG. 1). The sensor 112 (FIG. 1) may be able to monitor thisfrequency and that information to the plant control. In the event thatthe grid frequency is greater than a desired quantity, it may be assumedthat the wind farm is producing power at a rate that is below demand. Inthe event that the grid frequency is less than the desired quantity, itmay be assumed that the wind farm is producing power at a rate thatexceeds demand.

According to one embodiment, independent of commands sent by the plantcontroller 114 (FIG. 1) may modify the ramp up and ramp down rates basedon frequency of the grid. In general, the plant controller may increasepower production when the system frequency drops below a minimumfrequency threshold (f_(RRmin)) and decrease the power production whenthe system frequency is above maximum frequency (f_(RRmax)). Thisoperational mode may in one embodiment, be active between these twofrequency thresholds. Depending on whether the current operation of thewind farm is based on a ramp up rate or a ramp down rate, one of twopossible variations may be made. In the event that grid frequencydecreases towards f_(RRmin) the ramp up rate is increased to stabilizethe frequency and the ramp down rate is decreased to protect againstlarge power drops that may influence grid frequency. In the case of anincrease in frequency relative to the value of f_(RRmax), the abovedescribed behavior may be reversed. That is, the ramp up rate decreasesto protect against large power peaks, which may influence the gridfrequency, and the ramp down rate increases to stabilize the frequency.FIG. 5 shows a graph of the variations (or curves) of the ramp up rate502 and the ramp down rate 504 based on frequency. The graph in FIG. 5show grid frequency normalized with respect to f_(rated) for the grid(typically 60 Hz in the US) along the x-axis and the ramp rate for thefarm on the y-axis. Of course, the shape of the ramp up rate 502 andramp down rate 504 curves may take on any shape and those shown in FIG.5 are by way of example only.

In support of the teachings herein, various analysis components may beused, including digital and/or an analog system. The system may havecomponents such as a processor, storage media, memory, input, output,communications link (wired, wireless, pulsed mud, optical or other),user interfaces, software programs, signal processors (digital oranalog) and other such components (such as resistors, capacitors,inductors and others) to provide for operation and analyses of theapparatus and methods disclosed herein in any of several mannerswell-appreciated in the art. It is considered that these teachings maybe, but need not be, implemented in conjunction with a set of computerexecutable instructions stored on a computer readable medium, includingmemory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, harddrives), or any other type that when executed causes a computer toimplement methods of the present invention. These instructions mayprovide for equipment operation, control, data collection and analysisand other functions deemed relevant by a system designer, owner, user orother such personnel, in addition to the functions described in thisdisclosure.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

The invention claimed is:
 1. A method of operating a power productionfacility, the method comprising: receiving at a plant controller acurrent power production rate of the power production facility;receiving a power production rate requirement at the plant controllerfrom a utility receiving power from the power production facility;determining at the plant controller that the current power productionrate is either below or above the power production rate requirement;transmitting a signal from the plant controller to cause a powerproducing device to charge an energy storage device in the event thatthe current power production rate is above the power production raterequirement or to cause the energy storage device discharge in the eventthat the current power production rate is below the power productionrate requirement; and providing a signal to the utility that indicates aramp rate availability of the power production facility, the ramp rateavailability being calculated based on a relation between a possiblepower of the power production facility, a power set point, and a chargestatus of the energy storage device.
 2. The method of claim 1, furthercomprising: transmitting a signal from the plant controller to cause thepower producing device to ramp up in the event that the power productionrate is above the power production rate requirement; and transmitting asignal from the plant controller to cause the energy storage device tostore energy.
 3. The method of claim 1, further comprising: receiving asignal at the plant controller that the energy storage device is fullycharged; and transmitting a signal from the plant controller to causethe power producing device to ramp down.
 4. The method of claim 1,further comprising: providing an indication of a frequency at the outputof a power production facility to the plant controller.
 5. The method ofclaim 1, further comprising: creating a signal that causes powerproduction devices coupled to the plant controller to vary operationbased on the frequency at the output of the power production facility.